The present disclosure relates to pistons used in internal combustion engines fueled by gasoline, diesel, alcohol or any other combustible fuel. Internal combustion engine pistons are usually composed of two elements; a skirt and crown. While in service, pistons used in internal combustion engines, such as medium and heavy duty diesel engines, are exposed to extremely hot operating temperatures. To reduce the temperature of piston components, especially components adjacent to the combustion chamber, a cooling gallery may be provided within the piston crown. The cooling gallery may be formed by an interior volume located within the piston crown and may be covered with a piston crown cover plate. The cooling gallery is a permanent feature of the piston crown. A piston crown cover plate is typically located along a lower surface of the piston crown. The cooling gallery and crown cover plate generally define a chamber or channel having a permanently defined volume.
Due to severe thermal stresses generated by the hot combustion chamber temperatures, it may be necessary to cool the piston crown during engine operation. As one example, the piston crown for diesel engines may be cooled via an oil spray directed into the cooling gallery. The oil flows into the cooling gallery through an inlet aperture in the piston, and the reciprocating motion of the piston during engine operation generally moves the oil back and forth within the cooling gallery. Accordingly, at least part of the heat of the piston crown portion is removed. The heated oil typically exits the cooling gallery through an exit aperture in the piston, while fresh oil can be supplied to the cooling gallery through the inlet aperture.
Internal combustion engines, particularly medium and heavy duty diesel engines, include stringent cooling requirements due to the elevated combustion pressure and temperature within the combustion chamber. Moreover, to improve engine performance it has become increasingly desirable to operate engines at even higher combustion pressures and temperatures. Additionally, cooling requirements may vary depending on the intended operating conditions of a particular engine. Unfortunately, the existing cooling gallery formed in the piston crown may not always be able to meet the increasing cooling requirements or be fit for the intended cooling requirements of the piston crown in a particular engine.
Accordingly, there exists a need for a piston that will provide enhanced cooling properties when compared to the current pistons that are available today.